Structural and functional characterization of partner switching regulating the environmental stress response in Bacillus subtilis

J Biol Chem. 2007 Apr 13;282(15):11562-72. doi: 10.1074/jbc.M609733200. Epub 2007 Feb 15.

Abstract

The general stress response of Bacillus subtilis and close relatives provides the cell with protection from a variety of stresses. The upstream component of the environmental stress signal transduction cascade is activated by the RsbT kinase that switches binding partners from a 25 S macromolecular complex, the stressosome, to the RsbU phosphatase. Once the RsbU phosphatase is activated by interacting with RsbT, the alternative sigma factor, sigmaB, directs transcription of the general stress regulon. Previously, we demonstrated that the N-terminal domain of RsbU mediates the binding of RsbT. We now describe residues in N-RsbU that are crucial to this interaction by experimentation both in vitro and in vivo. Furthermore, crystal structures of the N-RsbU mutants provide a molecular explanation for the loss of interaction. Finally, we also characterize mutants in RsbT that affect binding to both RsbU and a simplified, binary model of the stressosome and thus identify overlapping binding surfaces on the RsbT "switch."

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus subtilis / chemistry*
  • Bacillus subtilis / genetics
  • Bacillus subtilis / metabolism*
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Crystallography, X-Ray
  • Gene Expression Regulation, Bacterial
  • Models, Molecular
  • Mutation / genetics
  • Phosphoric Monoester Hydrolases / chemistry
  • Phosphoric Monoester Hydrolases / genetics
  • Phosphoric Monoester Hydrolases / metabolism
  • Phosphorylation
  • Protein Binding
  • Protein Structure, Tertiary
  • Protein-Serine-Threonine Kinases / chemistry
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism
  • Surface Plasmon Resonance

Substances

  • Bacterial Proteins
  • RsbT protein, Bacillus subtilis
  • Protein-Serine-Threonine Kinases
  • Phosphoric Monoester Hydrolases
  • RsbU protein, Bacillus subtilis

Associated data

  • PDB/2J6Y
  • PDB/2J6Z
  • PDB/2J70